List排序

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

class Student {
    private String name;
    private Integer age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public Student(String name, Integer age) {
        super();
        this.name = name;
        this.age = age;
    }
    
    
}

public class Compar {
     public static void main(String[] args) {

          Student zlj = new Student("丁晓宇", 21);
          Student dxy = new Student("赵四", 22);
          Student cjc = new Student("张三", 11);
          Student lgc = new Student("刘武", 19);

          List<Student> studentList = new ArrayList<Student>();
          studentList.add(zlj);
          studentList.add(dxy);
          studentList.add(cjc);
          studentList.add(lgc);

          System.out.println("按年龄升序：");
          Collections.sort(studentList, new SortByAge());
          for (Student student : studentList) {
           System.out.println(student.getName() + " / " + student.getAge());
          }
          System.out.println();
          System.out.println("按姓名排序：");
          Collections.sort(studentList, new SortByName());
          for (Student student : studentList) {
           System.out.println(student.getName() + " / " + student.getAge());
          }
         }
        }

        class SortByAge implements Comparator {
         public int compare(Object o1, Object o2) {
          Student s1 = (Student) o1;
          Student s2 = (Student) o2;
          return s1.getAge().compareTo(s2.getAge());
//          if (s1.getAge() > s2.getAge())
//           return 1;
//          return -1;
         }
        }

        class SortByName implements Comparator {
         public int compare(Object o1, Object o2) {
          Student s1 = (Student) o1;
          Student s2 = (Student) o2;
          return s1.getName().compareTo(s2.getName());
         }
         

 

}